Earlier this week,, which prevents toy giveaways for meals that don't meet nutritional guidelines. Advocates have accused fast-food restaurants of predatory marketing to children and contributing to higher obesity rates.
The supervisors' 8-3 vote is enough to override Friday's veto by Mayor Gavin Newsom, who previously said he opposed the measure.
Newsom said that while the ban has good intentions, it's parents - not politicians - who should decide what their children eat.
The ordinance, which would go into effect in December of next year, prohibits toy giveaways in fast-food children's meals that have more than 640 milligrams of sodium, 600 calories or 35 percent of their calories from fat. The law also would limit saturated fats and trans fats and require fruits or vegetables to be served with each meal with a toy.
"Our effort is really to work with the restaurants and the fast-food industry to create healthier choices," said Supervisor Eric Mar, the measure's chief sponsor. "What our kids are eating is making them sick, and a lot of it is fast food."
The legislation is a big victory for activists and public health advocates who have charged food marketers with being complicit in the country's growing childhood obesity rates. They hope other cities and counties nationwide will follow their lead.
"This will be a sign to the fast-food industry that it's time to phase out its predatory marketing to children at large," said Deborah Lapidus, a senior organizer with Boston-based Corporate Accountability International, a watchdog group that supported the legislation.